Tissue stabilization

ABSTRACT

A tissue stabilizer includes a pneumatic rigidifying bladder which is flexible when at ambient pressure and rigid when at negative pressure or evacuated. Structure such as straps with hook-and-eye fasteners attaches the rigidifying bladder to tissue to be stabilized, such as a broken arm. When positioned on the tissue, the bladder is evacuated, thereby rigidifying the bladder and supporting the tissue. The tissue stabilizer may be configured for use in surgical procedures, such as performing coronary artery bypass grafting (CABG) on a warm, beating heart. In a cardiac embodiment, the tissue stabilizer includes an attaching bladder with a plurality of openings. When suction is applied at a port of the attaching bladder, suction is applied at the openings, which is utilized to attach the stabilizer to the epicardium of the heart. Once in position on the heart, suction may be applied at a port of the rigidifying bladder. When rigid, the heart may be moved as desired to perform CABG procedures.

RELATED APPLICATIONS

This application is a continuation of, and claims priority to U.S.patent application Ser. No. 09/268,556, entitled “Methods and Apparatusfor Stabilizing Tissue”, now U.S. Pat. No. 6,607,479, filed on Mar. 15,1999, which is a continuation-in-part of U.S. patent application Ser.No. 09/042,853, entitled “Methods and apparatus for stabilizing tissue”,which is now U.S. Pat. No. 6,251,065, filed on Mar. 17, 1998 and issuedon Jun. 26, 2001, which are both herein incorporated by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates in general to devices for stabilizingtissue and to methods for using such tissue-stabilizing devices,particularly cardiac tissue stabilizers. More particularly, the presentinvention relates to medical devices designed to stabilize the heart,for example, to retain the heart physically in an stabile position,during cardiac surgery. The apparatus of the present invention allows asurgeon to perform cardiac surgery on a warm beating heart, thuseliminating the need to place a patient on a cardiac bypass machine tostop the heart from beating. The methods and apparatus of the inventionare particularly useful when performing coronary artery bypass graftingprocedures such as coronary anastomosis.

BACKGROUND OF THE INVENTION

There are many instances in which tissue needs stabilization. One commoninstance is in the case of broken bones. Broken bones need to be set andthen held rigid and in a stabile position by a cast in order to healproperly. Sprained joints, such as sprained ankles, wrists, and fingers,also require tissue stabilization. In these cases, splints, tapes, andbandages are often used to maintain the joint in a relatively stabileposition. Other instances include neck and spinal injuries.

In addition to these examples of external tissue stabilization, internalorgans may also need to be stabilized for specific medical procedures.For example, the heart may need to be stabilized during cardiacprocedures. One such procedure is coronary artery bypass graft surgery(CABG), which is the most commonly performed cardiac operation,accounting for over 80% of all cardiovascular surgery. Indeed, more than400,000 CABG operations were performed in 1997 alone. The clinicalspectrum of presenting problems resulting in consideration for CABGincludes angina, unstable angina, congestive heart failure due toischemia, myocardial infarction, survival of sudden cardiac death, andasymptomatic ischemia. In recent years, the profile of a typical CABGpatient has expanded to include higher-risk patients, such as olderpatients and patients with more advanced stages of coronary arterydisease, as well as patients for “re-do” operations who have already hadat least one CABG operation. The effect of these changes is reflected inthe higher morbidity and mortality associated with these higher-riskpatients.

One of the risks involved in performing CABG is that the heart isstopped to provide a stabile operating platform. This is accomplishedthrough the use of catheters, a heart-lung machine, and cardioplegia.After the procedure has been finished, the heart needs to bedefibrillated. Risks involved in stopping the heart include damage fromthe catheters such as in the creation of thrombi and the possibilitythat the heart will not defibrillate.

In recent years, advances have been made so that the heart does not needto be stopped in order to perform CABG procedures, allowing CABG to beperformed on a warm, beating heart. To do so, a relatively stabileoperating platform needs to be maintained. Conventional apparatusdeveloped to provide a stabile operating platform include devices whichapply pressure against the heart and devices with a finger-shapedconfiguration which adhere to the heart through suction. To apply thesedevices to the heart, it takes both of the surgeon's hands to positionthe devices on the heart. In addition, the devices do not establishsecure contact with the epicardium of the heart and often need to berepositioned during the CABG procedure, which is time consuming and anuisance.

In view of the foregoing, one of the objectives of the present inventionis to provide methods and apparatus for stabilizing tissue whichovercome the drawbacks of conventional techniques.

It is another object of the present invention to provide methods andapparatus for stabilizing a heart during cardiac procedures,particularly a warm, beating heart.

It is yet another object of the present invention to provide methods andapparatus for stabilizing tissue which may be applied at remotelocations.

It is still another object of the present invention to provide methodsand apparatus for stabilizing tissue with pneumatics.

SUMMARY OF THE INVENTION

These and other objects are achieved by the tissue stabilizers of thepresent invention and the method for their use which stabilize tissuethrough the use of pneumatics. In accordance with broad, functionalaspects of the present invention, the tissue stabilizer of the inventionincludes a bladder which is substantially flexible when at ambientpressure. However, when subject to negative pressure, such as throughsuction or vacuum, the bladder becomes substantially rigid. Because ofthese features, in use the tissue stabilizer may be positioned on tissueto be stabilized by, for example, wrapping the stabilizer around thetissue in the case of an arm, or contouring the stabilizer to thesurface topography of the tissue in the case of a heart. When in adesired position, the rigidifying bladder may be subject to negativepressure, thereby rigidifying the tissue stabilizer. When rigid, thetissue stabilizer maintains the tissue in a stable position. The tissuestabilizer is particularly useful when configured for performingcoronary artery bypass procedures (CABG) on a warm, beating heart.

In accordance with one aspect of the present invention, a tissuestabilizer includes a flexible rigidifying bladder and means forattaching the rigidifying bladder to tissue to be stabilized, such asstraps with hook-and-eye fasteners. The rigidifying bladder includes achamber, a port through which the chamber is evacuatable, andrigidifying structure disposed within the chamber. The rigidifyingstructure is configured to be substantially rigid when the chamber isevacuated. When the chamber is at ambient pressure, the rigidifyingstructure is substantially flexible to allow the stabilizer to becontoured to the tissue. The tissue stabilizer may include a valve forsealing the chamber when evacuated to maintain rigidity of the bladder.

The rigidifying structure may include opposing layers of mesh betweenwhich a plurality of movable beads are disposed. When the chamber ispneumatically evacuated, the rigidifying bladder collapses, therebydrawing the opposing layers of mesh together which, in turn, urges thebeads together. The frictional forces between the beads and the meshresist movement relative to each other, thereby providing rigidity. Therigidifying structure may include a plurality of walls which divide theinner chamber into a plurality of cells. The cells may be connected byair passages. The dividing walls prevent the migration of beads, therebymaintaining a substantially consistent distribution of beads andsubstantially consistent rigidity across the extent of the stabilizer.

The rigidifying bladder may also include a plurality of inner wallswhich separate the chamber into layers. The inner walls may include airpassages so that each of the layers is in pneumatic communication witheach other. The rigidity of the rigidifying bladder is generallyproportional to the number of layers. For example, in embodiments of thestabilizer configured to stabilize broken bones, the chamber may bedivided into four or five layers, each of which includes a pair ofopposing layers of mesh and a plurality of movable beads.

The tissue stabilizer of the present invention may be configured formany medical applications. For example, the tissue stabilizer may beconfigured as a portable neck brace for use by emergency medical teamsfor supporting and stabilizing an injured patient's neck. The stabilizermay serve as a cast or a splint for stabilizing a broken bone that hasbeen set. The tissue stabilizer may also be configured for athleticapplications, such as protective gear or ankle support. The tissuestabilizer of the present invention is particularly useful instabilizing the heart during cardiac procedures.

In this regard, an alternative embodiment of the tissue stabilizer ofthe present invention for cardiac applications includes a flexible firstbladder for attaching the cardiac stabilizer to the heart and a flexiblesecond bladder for rigidifying the stabilizer. Both bladders include aninner chamber and a port through which the chamber may be evacuated. Thefirst bladder includes a plurality of openings which apply suction inresponse to suction applied at the port thereof. The second bladderincludes rigidifying structure which rigidifies in response to suctionapplied at the port thereof. The cardiac stabilizer may includeretaining structure which may be engaged with an external support forretaining the tissue stabilizer in a desired position when rigid. Thecardiac stabilizer may also include a window for providing access to asurgical site.

In using the cardiac stabilizer to perform surgery, after providingaccess to the heart, the stabilizer is placed on the epicardium of theheart at a desired location, preferably with the window positioned overthe surgical site. Suction is then applied at the port of the attachingbladder, thereby attaching the stabilizer to the heart. Suction thenapplied at the port of the rigidifying bladder, thereby rigidifying thecardiac stabilizer. A coronary artery bypass procedure may then beperformed on the heart.

One of the advantages of the present invention is that the cardiacstabilizer may be contoured to the surface topography of the heart. Thisallows the attaching bladder to make secure contact with the heart,particularly when the heart has not been placed on a bypass machine(e.g., a heart-lung machine) but is warm and beating. The contouringallows the warm heart to be securely retained by the stabilizer,allowing the heart to be moved from the cardiac anatomical position toan anastomosis position. This is particularly advantageous whenperforming a bypass procedure on the circumflex branch of the leftcoronary artery. When the heart has been moved into an anastomosisposition, the retaining structure of the cardiac stabilizer may beattached to external support structure to retain the heart in theanastomosis position.

One of the advantages of the invention is that the tissue stabilizer maybe disengaged from the external support structure, de-rigidified, anddetached from the tissue. This allows the stabilizer to be repositionedand then re-rigidified. In cardiac applications, such as on warm,beating hearts, the cardiac stabilizer may be disengaged from theexternal support, allowing the heart to be returned to the cardiacanatomical position if the heart should experience hemodynamicinstability. When the heart regains stability, the heart may berepositioned in the anastomosis position and re-engaged with theexternal support.

Other objects, features, and advantages of the present invention willbecome apparent to those skilled in the art from a consideration of thefollowing detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the present invention in the context of a cardiac tissuestabilizer but which are equally relevant to stabilizers for supportingother types of tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary tissue stabilizerconfigured as a cardiac stabilizer in accordance with the presentinvention, particularly illustrating a top surface of the stabilizer;

FIG. 2 is a perspective view of the cardiac stabilizer, particularlyillustrating a bottom surface of the stabilizer;

FIG. 3A is a cross-sectional view of the cardiac stabilizer taken alongline 3—3 of FIG. 1, particularly illustrating a rigidifying bladderwithout applied suction;

FIG. 3A′ is view similar to that of FIG. 3A, particularly illustratingthe rigidifying bladder with applied suction;

FIG. 3B is a cross-sectional view of the cardiac stabilizer taken alongline 3—3 of FIG. 1, illustrating an alternative embodiment of thestabilizer;

FIG. 3C is a cross-sectional view of the cardiac stabilizer taken alongline 3—3 of FIG. 1, illustrating yet another alternative embodiment ofthe stabilizer;

FIG. 4 is a cross-sectional view of the cardiac stabilizer taken alongline 4—4 of FIG. 3;

FIG. 5 is a cross-sectional view of the cardiac stabilizer taken alongline 5—5 of FIG. 1;

FIG. 5A is an enlarged fragmentary cross-sectional view of a rigid plateand rigidifying structure of the invention;

FIG. 5B is a cross-sectional view of a rigidifying structure of theinvention;

FIG. 6 is a plan view of the cardiac stabilizer, particularlyillustrating an exemplary embodiment of engaging structure of theinvention;

FIG. 7 is a plan view of the cardiac stabilizer, illustrating analternative embodiment of the engaging structure of the invention;

FIG. 8 is a cross-sectional view of the cardiac stabilizer taken alongline 8—8 of FIG. 7;

FIG. 9 is a cross-sectional view of the cardiac stabilizer taken alongline 9—9 of FIG. 7;

FIG. 10 is a schematic view of a tissue stabilizer of the presentinvention in use during a cardiac procedure on a heart;

FIG. 11 is a perspective view of a tissue stabilizer configured inaccordance with the present invention;

FIG. 12A is a cross-sectional view of the tissue stabilizer taken alongline 12—12 of FIG. 11, particularly illustrating the tissue stabilizerat ambient pressure;

FIG. 12B is view similar to that of FIG. 12A, particularly illustratingthe tissue stabilizer at negative pressure;

FIG. 13 is a fragmentary cross-sectional view of attaching straps of thetissue stabilizer, particularly illustrating a pressure-sensitiveadhesive embodiment;

FIG. 14 is a fragmentary cross-sectional view of an alternativeembodiment of the attaching straps of the tissue stabilizer,particularly illustrating a cohesive adhesive embodiment;

FIG. 15 is a schematic view of the tissue stabilizer of the inventionconfigured for use with a leg;

FIG. 16 is a perspective view of exemplary rigidifying structure of thetissue stabilizer of the present invention;

FIG. 17A is a cross-sectional view of the exemplary rigidifyingstructure taken along line 17—17 of FIG. 16, particularly illustratingan embodiment of a dividing wall at ambient pressure;

FIG. 17B is a view similar to that of FIG. 17A, particularlyillustrating the dividing wall at negative pressure;

FIG. 18 is a fragmentary cross-sectional view of another embodiment of adividing wall of exemplary rigidifying structure of the invention;

FIG. 19 is a fragmentary cross-sectional view of yet another embodimentof a dividing wall of exemplary rigidifying structure of the invention;

FIG. 20 is a schematic view of the tissue stabilizer of the presentinvention configured for use in stabilizing a neck;

FIG. 21 is a schematic view of the tissue stabilizer of the inventionconfigured for use in stabilizing an arm;

FIG. 22 is a schematic view of a shoe in accordance with the inventionin which the tissue stabilizer is configured as a liner for providingheel fit and/or ankle support;

FIG. 23 is a schematic view of a tissue stabilizer of the presentinvention in use during a cardiac procedure on a heart; and

FIG. 24 is a schematic view of a tissue stabilizer of the presentinvention in use with a trocar sheath.

DETAILED DESCRIPTION OF THE INVENTION

Referring more particularly to the drawings, an exemplary tissuestabilizer 10 configured in accordance with the teachings of the presentinvention is illustrated in FIGS. 1 and 2. For descriptive purposes andwithout limiting the scope of the present invention, exemplarystabilizer 10 is illustrated as a cardiac stabilizer for stabilizing aheart during surgical procedures, particularly surgical procedures whichare performed on a heart which is not immobilized but rather which iswarm and beating. Tissue stabilizers configured for alternativefunctions are contemplated as being within the scope of the invention aswill be understood by those skilled in the art. Those skilled in the artwill also appreciated that exemplary tissue stabilizer 10 utilizedduring cardiac procedures must be biocompatible and possesssubstantially atraumatic features. However, these additional propertiesmay not be essential to all tissue stabilizers produced in accordancewith the teachings of the invention.

Exemplary tissue stabilizer 10 is substantially flexible and isconformable to the shape or anatomical topography of a particular pieceor section of tissue, such as the epicardium of the left ventricle of aheart. Tissue stabilizer 10 is also attachable to tissue in asubstantially atraumatic manner through, for example, the use of suctionapparatus. Furthermore, stabilizer 10 may be rigidified to maintain adesired shape through the use of auxiliary suction apparatus. Each ofthese features of the present invention will be described in detailbelow.

With additional reference to FIG. 3A, exemplary stabilizer 10 includesstructure for attaching the stabilizer to tissue, such as an attachingbladder 12, and structure for becoming substantially rigid uponactuation, such as a rigidifying bladder 14. Attaching bladder 12 has aport 16 leading into an inner chamber 18 in which a plurality ofopenings 20 are formed. Exemplary bladder 12 is substantially flexibleand configured so that openings 20 apply suction when suction is appliedat port 16. Rigidifying bladder 14 has a port 22 leading into an innerchamber 24 in which rigidifying structure 26 is disposed. A portion ofrigidifying structure 26 may be attached to bladder 14, and a portion ofthe rigidifying structure may be unattached or free floating. In FIG.3A, free-floating rigidifying structure is exemplified in the figures bysubstantially spherical beads or balls, although any structuredconfigured in accordance with the principles of the present inventionmay be utilized. In addition, rigidifying structure 26 may be configuredas a mesh-like sheet or as a corrugated sheet of material made from, forexample, nylon implanted or impregnated with silicone. At least aportion of the mesh-like or corrugated sheet may be attached torigidifying bladder 14. (The dimensions for the components of stabilizer10 in the drawings, for example, the thickness of the walls of bladders12 and 14 are exaggerated for illustrative purposes.)

Referencing FIGS. 3A and 3A′, exemplary bladder 14 is configured to besubstantially flexible when suction is not applied at port 22, which isshown in FIG. 3A, and substantially rigid when suction is applied atport 22, which is shown in FIG. 3A′. As shown in FIG. 3A, inner chamber24 has an ambient volume which provides space in which portions ofrigidifying structure 26 may move with respect to each other, allowingbladder 14 to bend and flex. However, when suction is applied at port22, negative pressure or a vacuum is induced within inner chamber 24,causing bladder 14 to collapse upon itself, as shown in FIG. 3A′. Innerchamber 24 now has a collapsed volume which is less than the ambientvolume, and the space among rigidifying structure 26 is substantiallyreduced, thereby increasing the density of the rigidifying structure.Accordingly, individual portions of rigidifying structure 26 are urgedtogether under pneumatic force and resist relative movement with respectto each other. As shown in the drawings, structure such as free-floatingbeads engage with spaces formed between attached beads to resist lateralmovement relative to each other. If rigidifying structure 26 isconfigured as a mesh, then free-floating beans partially lodge withinopenings in the mesh. With the individual portions of rigidifyingstructure 26 urged together under vacuum to resist relative movement,collapsed bladder 14 is substantially inflexible, resists bending, andretains a stiffened position.

In this regard, a surgeon may apply and conform stabilizer 10 to tissueso that preferably a majority of the openings 20 contact or are incidenton the tissue. Suction may be applied at port 16, causing suction to beapplied at the openings 20 and thereby attaching stabilizer 10 to thetissue. Suction may then be applied at port 22 to stiffen or rigidifystabilizer 10, causing the stabilizer to maintain a desired position andconfiguration on the tissue. In applying exemplary stabilizer 10 totissue in this matter, the surgeon may manipulate the tissue as desiredby manipulating the stabilizer because the tissue is retained by thestabilizer. Accordingly, the retained tissue moves when the stabilizermoves or maintains a stabilized position when the stabilizer ismotionless or anchored. A surgeon may then operate on the physicallyimmobilized tissue without distraction or error caused by moving tissue.

An alternative embodiment of exemplary stabilizer 10 is illustrated inFIG. 3B. In this embodiment, exemplary attaching bladder 12 isconfigured so that inner chamber 18 is divided into a plurality of cells28 which are connected by a plurality of air passages 30 formed throughdividing walls 32. Each cell 28 may be elongate in shape, extendingsubstantially from one side of bladder 12 to the other. Accordingly,each cell 28 may include a number of openings 20 disposed in a row alongan extent thereof, such as illustrated in FIG. 2.

Also illustrated in FIG. 3B, exemplary rigidifying bladder 14 isconfigured so that inner chamber 24 is divided into a plurality of cells34 which are connected by a plurality of air passages 36 formed throughdividing walls 38. Each cell 34 of rigidifying bladder 14 may beelongate in shape, extending substantially from one side of bladder 14to the other. Each cell 34 includes rigidifying structure 26 which maybe disposed either attached to an inner wall of bladder 14 and/ordividing walls 38, free floating, or in a combination of both as shownin FIG. 3B. Free-floating rigidifying structure 26 may include sphericalballs which are dimensioned to be larger than air passages 36 to preventpassage therethrough, as shown in FIG. 3B.

Another alternative embodiment of the tissue stabilizer of the presentinvention is illustrated in FIGS. 3C and 4. Rather than attachingbladders 12 and 14 in a substantially coplanar and coextensiverelationship as shown in FIGS. 3A and 3B, attaching bladder 12 isimbedded within rigidifying bladder 14 in exemplary stabilizer 10 shownin FIGS. 3C and 4. In this embodiment, attaching bladder 12 includes aplurality of branching arms 40 which extend from a central channel 42.Each arm 40 provides a pneumatic conduit to a number of the openings 20of attaching bladder 12, thereby providing communication for eachopening 20 to port 16 via the inner chamber 18. Rigidifying bladder 14exemplified in FIGS. 3C and 4 may include an inner wall 44 whichseparates the inner chamber 24 into two layers or sections. Wall 44includes at least one air passage 46 so that each section of chamber 24is in pneumatic communication with port 22. Rigidifying structure 26 mayinclude attached as well as free-floating structure analogous to thedescription above. Although a single inner wall 44 is illustrated,rigidifying bladder 14 may include a plurality of walls 44 to separateinner chamber 24 into a plurality of sections or layers.

Referencing FIGS. 1 and 5, exemplary tissue stabilizer 10 of theinvention may also include retaining structure 50 for engaging withexternal support apparatus. Exemplary retaining structure 50 may includea substantially rigid plate 52 and engaging structure 54. Plate 52 maybe attached to either or both of the bladders 12 or 14 with, forexample, adhesive or sewing. (Components of bladders 12 and 14 asdescribed above are not shown in FIG. 5 for clarity.) Exemplary plate 52may include a window 56 which provides a surgeon access to a surgicalsite on the tissue to which stabilizer 10 is attached. In the embodimentillustrated in the drawings, tissue stabilizer 10 and plate 52 haveU-shape configurations, thereby defining window 56.

Although illustrated as a three-sided opening, exemplary window 56 maybe four sided, that is, enclosed on all four sides. In addition, window56 may be curvilinear (rather than rectilinear as shown) and may beoffset from a medial axis of the tissue stabilizer (rather than centeredas shown). Stabilizer 10 may be configured so that window 56 is wider ata top surface of the stabilizer and narrower at a bottom surface of thestabilizer, or vice versa. In addition, multiple windows 56 may beformed in the tissue stabilizer. In a multiple window embodiment,windows 56 may function as a vent for promoting or facilitating aircirculation, which will be discussed in reference to alternativeembodiments of the tissue stabilizer of the invention below.

In another multiple window embodiment shown in FIG. 23, the multiplewindows 64 may be arranged into a grid pattern to facilitate delivery ofa medical therapy which may include Transmyocardial Revascularization(TMR) or intramyocardial injection of angiogenic or myocardial cellgrowth substance. A delivery device 66 is depicted. The shape andoperation of delivery device 66 is not germane to the present invention,and may be any delivery device known to those skilled in the art. Thisembodiment incorporates a doppler ultrasound probe 68 to align thestabilizer 10 thereby avoiding vessel puncture. The grid pattern may bemodified as necessary to facilitate the therapy and to avoid damage toareas not intended to receive the therapy. The windows 64 may be sizedas desired, their numbers may be modified, and their orientations may bealtered as medically necessary.

As shown in FIG. 24, the stabilizer 10 is rolled and loaded into atrocar sheath 67 to be deployed through a port access, as through anopening in the chest wall. Once deployed and properly positioned on theheart 70, the stabilizer 10 facilitates port delivery of TMR,intramyocardial injection of therapy or coronary anastomosis withrobotic arms.

Referencing FIG. 5A, the junction of rigid plate 52 and the bladders(either or both of bladders 12 and 14) may be configured at astress-reducing section 57. For example, rigidifying bladder 14 mayinclude rigidifying structure 26′ configured as a flexible nylon mesh,and plate 52 may be made from a substantially rigid nylon, with section57 being defined as an integral transition therebetween. Stress-reducingsection 57 is more resilient than rigid plate 52 but less resilient thanmesh 26′, thereby allowing the mesh to flex with respect to the plate.

Exemplary engaging structure 54 may be configured as a ball 58 disposedon a post 60, with the post being attached to plate 52 and projectingaway from the bladders 12 and 14. As shown in the drawings, engagingstructure 54 includes a pair of balls 58 and posts 60. Balls 58 areconfigured to releasably engaging with complement external supportstructure, such as quick-release sockets with by a single flip leveroperated with one hand as known in the art, which will be discussed inmore detail below. Referring to FIG. 6, engaging structure 54 mayinclude a plurality ball-and-post structures (58 and 60) arranged ontissue stabilizer 10. The plural balls 58 may be configured so thatexternal support structure engages with at least two of the balls 58simultaneously. As such, tissue stabilizer 10 is retained in asubstantially rigid manner in all dimensions.

An alternative embodiment of the engaging structure of the presentinvention is illustrated in FIGS. 7, 8, and 9. Components of thealternative engaging structure 54′ analogous to those shown in FIGS. 1and 5 are reference with like numerals with the addition of a prime (′).Exemplary engaging structure 54′ may include a cross bar 62 extendingbetween a respective pair of posts 60′ connected to rigid plate 52′. Asshown in the drawings, a pair of cross bars 62 are provided. Each crossbar 62 is substantially rigid and provides an extended structure towhich external support apparatus may be easily attached. When attached,tissue stabilizer 10 is pivotal only about a single axis, that is, theaxis of the cross bar which is engaged with external structure. Asparticularly shown in FIG. 8, each cross bar 62 may have a polygonalcross section, for example, a hexagon.

FIG. 10 illustrates a preferred implementation of exemplary tissuestabilizer 10 of the present invention in which the stabilizer 10stabilized the heart 70 during a surgical procedure. The heart 70includes the left coronary artery 72 and the right coronary artery 74.The left coronary artery 72 includes the anterior descending branch 76and the circumflex branch 78 which runs to the posterior side of theheart 70. In the example shown, the left coronary artery 72 has adiseased portion 80 which restricts the flow of oxygenated blood fromthe aorta 82. A coronary artery bypass grafting (CABG) procedure may beperformed on the heart 70 to bypass the diseased portion 80. A coronaryanastomosis is a CABG procedure which providing a graft 84 between theleft coronary artery 72 and the internal mammary artery 86.

In order to perform a coronary anastomosis, a stable operating platformmust be provided for the surgeon; that is, the heart 70 must bestabilized. This may be accomplished by placing the patient on aheart-lung machine and stopping the heart from beating withcardioplegia. Alternatively, coronary anastomosis may be performed on aheart which not stopped but which is warm and beating. Prior toutilizing the tissue stabilizer of the invention, access to the heart 70is provided as known in the art, such as through a medial sternotomy orthoracotomy, which may also involve a retractor. Access may also beprovided in a substantially minimally invasive manner, such asintercostally through a trocar sheath or a “mini” thoracotomy.

In accordance with the present invention, stabilizer 10 may be appliedto the heart 70 to stabilize the heart 70 at surgical site 88, therebyproviding a stable operating platform for the surgeon. To perform CABGprocedures with tissue stabilizer 10 of the invention, ports 16 and 22of the stabilizer are connected to a source for suction, such as wallsuction 90. Stabilizer 10 may include a pair of valves 92 and 94 forregulating the suction between the wall suction 90 and ports 16 and 22,respectively. Cardiac stabilizer 10 may then be positioned on theepicardium of the heart 70, with window 56 positioned to provide accessto the surgical site 88. As shown, the coronary artery 72 is positionedwithin window 56. When in a desired position, suction may be applied atport 16 of the attaching bladder by, for example, actuating valve 92,thereby attaching or securing the stabilizer to the epicardium of theheart 70.

The suction applied to port 16 is at a level which minimizes orsubstantially prevents trauma to the epicardium. Depending upon theconfiguration of attaching bladder 12, such as the size and/or number ofopenings 20, the level of applied suction may range from, for example,about 50 millimeters of mercury (mm Hg) to about 150 mm Hg. Thispressure range may be at the lower end of the scale if a relativelylarge number of openings 20 are provided and at the higher end of thescale if a relatively small number of openings 20 are provided.

The applied suction may attach stabilizer 10 to the heart 70 with alevel of force which allows the stabilizer to be moved or slid acrossthe tissue under hand pressure. This feature facilitates the positioningof stabilizer 10 to a desired location. It also enables flexiblestabilizer 10 to be contoured to the anatomical topography of the heart70, providing optimal contact or incidence of the openings 20 on thesurface of the epicardium. As shown in FIG. 10, stabilizer 10 conformsto the left ventricle much like a patch, substantially “wrapping” arounda portion thereof. The U-shape configuration of stabilizer 10 allows thesurgeon to place a hand on the stabilizer with his or her fingersstraddling window 56, which ergonomically facilitates the positioningand contouring thereof. Only one hand is needed to position the cardiacstabilizer on the heart.

Once contoured and positioned as desired, suction may be applied at port22 of rigidifying bladder 14 by, for example, actuating valve 94,thereby stiffening stabilizer 10 and maintaining the desired contour.The suction applied at port 22 is at a level which retards bending andflexing of stabilizer 10 under hand pressure. Depending upon theconfiguration of rigidifying bladder 14, such as the size and/or numberof free-floating rigidifying structures 26, the level of suction appliedat port 22 may range from, for example, about 80 mm Hg to about 120 mmHg. For many cardiac applications, the suction applied to port 22 issuch that stabilizer 10 is rigid to about 5 pounds to 10 pounds offorce.

Once suction is applied to both ports 16 and 22 as described above,stabilizer 10 is attached and rigid, with the heart 70 being in itsnormal cardiac anatomical position. The tissue of the heart 70 to whichcardiac stabilizer 10 is attached is stabilized, as well as the coronaryartery 72 positioned within window 56. Stabilizer 10 may then be raised,thereby also raising the heart 70 to a position at which the coronaryanastomosis may be best performed. Once the heart 70 is in a desiredanastomosis position, stabilizer 10 may be attached to external supportstructure 96 to retain the stabilizer and, therefore, the heart 70 inthe anastomosis position.

External support structure 96 may include an articulated arm 98 with asocket 100, preferably a quick-release socket as shown, which isreleasably engageable with ball 58 of stabilizer 10. Although aball-and-socket arrangement is used for the purposes of thisdescription, any complementary releasable fastening means may beimplemented. External support structure 96 may include a sternalretractor 102 or a bedpost 104 to which support arm 98 is attachable.Articulated support arm 98 may bendable under sufficient hand force.Alternatively, arm 98 may be substantially flexible for positioning andthen made rigid through the use of a tensioning cable mechanism, asknown in the art. Although only one support arm 98 is shown, externalsupport structure 96 may include a second support arm attached to thesecond ball-and-post arrangement (58 and 60) of stabilizer 10. Oncestabilizer 10 is retained by the external support structure 96, theheart 70 is in a stable position and the coronary anastomosis may beperformed.

In certain patients, when the heart 70 is moved form the normal cardiacanatomical position to the anastomosis position, hemodynamic instabilitymay occur and threaten the health of the patient. To stop thehemodynamic instability, the heart 70 needs to be returned to thecardiac anatomical position, preferably in an expedient manner. Inaccordance with the present invention, tissue stabilizer 10 may bereleased from external support structure 96 by disengaging quick-releasesocket 100 from ball 58, allowing the stabilizer and the heart 70 to bemoved and lowered to the cardiac anatomical position. After the heart 70has recovered, stabilizer 10 may be raised to replace the heart 70 inthe anastomosis position, as described above. This quick-release featureof the invention is particularly useful if the coronary anastomosis isbeing performed on the circumflex branch 78 of the left coronary artery72. To perform such a procedure, the heart 70 needs to be lifted and/orrotated to a substantial degree out of the normal cardiac anatomicalposition to provide access to the circumflex branch 78 which is locatedat the posterior of the heart 70.

Returning to the level of suction applied to attaching bladder 12, ifthe coronary anastomosis is performed on the anterior descending branch76 of the coronary artery 72, then the heart 70 does not need to bemoved a substantial degree to provide access to the surgical site 88.However, if the coronary anastomosis is performed on the circumflexbranch 78 of the coronary artery 72, then the heart 70 needs to be movedor rotated a substantial degree to provide access to the surgical site.As the heart 70 may weigh about eight pounds in an average human, asubstantial amount of force is required to maintain the heart 70 in thedesired anastomosis position. Accordingly, the level of suction appliedto port 16 to attach stabilizer 10 to the heart 70 may be higher whencoronary anastomosis is performed on the circumflex branch 78 than whenperformed on the anterior descending branch 76. For example, about 100mm Hg to about 200 mm Hg may be applied to port 16 in the case of thecircumflex branch 78, and about 50 mm Hg to about 150 mm Hg may beapplied to port 16 in the case of the anterior descending branch 76. Formore specific values, these exemplary ranges may be limited to about 120mm Hg in the circumflex instance and about 80 in the anterior descendinginstance. In addition, the combination of level of applied suction andthe number and/or size of the openings 20 may be configured to retain upto about 25 pounds of force that the heart 70 may apply when moved toprovide access to the circumflex branch 78 of the coronary artery 72.Similarly, the external support structure 96, particularly socket 100may be configured to tolerate up to about 50 pounds or more of force.

During the coronary anastomosis, the heart 70 may be repositioned asdesired by bending or repositioning articulated arm 98. Alternatively,the heart 70 may be repositioned by releasing stabilizer 10 from supportarm 98, repositioning the stabilizer and heart as desired, and thenreattaching the stabilizer to the ann. After the coronary anastomosis iscompleted, stabilizer 10 may be detached from the external supportstructure 96, allowing the heart 70 to be returned to the normal cardiacanatomical position. The suction may then be disconnected from ports 16and 22 by actuating valves 92 and 94. Accordingly, stabilizer 10 becomesflexible and unattached to the heart 70 and may be removed. As manypatients require more than one bypass to be performed, the surgeon maythen reapply stabilizer 10 to another portion of the heart 70 toperformed another CABG procedure, such as on the right coronary artery74, in the manner described above. This reapplying of the stabilizer 10may continued a plurality of times to perform as many CABG are necessaryfor the patient.

In a commercial medical embodiment of tissue stabilizer 10, bladders 12and 14 may be made from substantially pneumatically impervious andbiocompatible material such as silicone or rubber. Rigidifying structure26 may be made from silicone or epoxy material or from metal and mayinclude free-floating metal or epoxy beads. Rigidifying structure 26 mayalso be made from nylon-reinforced silicone mounted to bladder 14.Retaining structure 54 may be made for stainless steel or other suitablyrigid material such as nylon.

The overall dimensions of stabilizer 10 configured for cardiac use maybe about 10 centimeters (cm) to about 15 cm in width and length and maybe about 0.5 cm to about 2 cm in thickness. Window 56 may be about 0.5cm to about 2 cm in width and at least about 3 cm in length. Openings 20may be about 0.25 cm to about 1 cm in diameter. Ball 58 may have adiameter of about 0.5 cm to 1 cm and may project above a top surface ofstabilizer 10 by about 0.75 cm to about 3 cm.

The foregoing description of the present invention focused on exemplarytissue stabilizer 10 for cardiac applications. However, as previouslymentioned, the tissue stabilizer of the present invention may beconfigured in accordance with many other applications. Broadly speaking,the teachings of the present invention are applicable to any situationwhich requires tissue stabilization. As will be described below, thetissue stabilizer of the present invention may be configured tostabilize, for example, an injured neck, a broken leg or arm, and asprained wrist or foot. Those skilled in the art will appreciate anynumber of additional applications of the tissue stabilizer from theteachings herein.

In this regard, FIG. 11 illustrates a tissue stabilizer 110 whichincludes flexible complementary straps 112 and a flexible rigidifyingbladder 114 attached to the straps. As a referencing convention herein,straps are generally referenced by numeral 112 and specificallyreferenced with an alpha suffix 112 a and 112 b, which convention willbe used analogously for other elements of the invention. With additionalreference to FIGS. 12A and 12B, analogous to the cardiac tissuestabilizer described above, rigidifying bladder 114 of exemplary tissuestabilizer 110 includes an inner chamber 116 defined therein and a port118 in communication with chamber 116 and through which the chamber maybe evacuated. Exemplary rigidifying bladder 114 also includesrigidifying structure 120 disposed within chamber 116 which isconfigured to be substantially flexible when the chamber is at ambientpressure or not evacuated, as shown in FIG. 12A, and substantially rigidwhen the chamber is evacuated through port 118 or under vacuum, as shownin FIG. 12B. When rigidified, tissue stabilizer 110 providessubstantially rigid support to tissue.

Similar to attaching bladder 12 of the cardiac stabilizer describedabove, flexible straps 112 provide a means for attaching rigidifyingbladder 114 to tissue to be stabilized. For example, with reference toFIG. 15 in which tissue stabilizer 110 is configured for application toa leg, once flexible rigidifying bladder 114 is positioned and wrappedaround the leg, straps 112 attach and secure the rigidifying bladder inplace. Each strap 112 a and 112 b may include complementary fasteningmeans for releasably securing the straps together, such as hooks 122 aand eyes 122 b (for example, Velcro®). Exemplary tissue stabilizer 110may include a plurality of complementary pairs of straps 112, which willbe discussed below.

Alternatively, straps 112 may include adhesive for releasably securingthe straps together. As shown in FIG. 13, strap 112 a may includepressure-sensitive adhesive 124, and strap 112 b may include a tab 126to which pressure-sensitive adhesive 124 is adherent. And as shown inFIG. 14, strap 112 a may include cohesive adhesive 128 a, and strap 112b may include cohesive adhesive 128 b which is complementary to adhesive128 a. As known in the art, cohesive adhesives are only adherent when incontact with each other but are not tacky to human touch. In addition tothe hook-and-eye fasteners (122) and the adhesive (124 and 128), otherfastening means may be used such as snaps, buckles, and so on. Flexiblestraps 112 may be made from elastic or inelastic material, dependingupon the application.

Referencing FIGS. 12A, 12B, and 16, exemplary rigidifying structure 120may include mesh 130 attached to bladder 114 and a plurality of movablebeads 132. Chamber 116 is preferably configured with opposing layers ofmesh, referenced as 130 a and 130 b, between which a plurality of beads132 are disposed. When chamber 116 is at ambient pressure (i.e., notevacuated or under vacuum), rigidifying bladder 114 and, accordingly,tissue stabilizer 110 are flexible, as shown in FIG. 12A. However, whenchamber 116 is evacuated through port 118, rigidifying bladder 114collapses under the negative pressure, drawing opposing layers of mesh130 a and 130 b together. Beads or balls 132 lodge within recesses 134in mesh 130 and are urged therein under the applied negative pressure,thereby rigidifying the bladder, as shown in FIG. 12B. Rigidifyingbladder 114 may include a valve 136 disposed over port 118 which may beclosed to retain the vacuum of chamber 116, thereby retaining therigidity of bladder 114.

Rigidifying bladder 114 may include a plurality of walls 138 whichseparate inner chamber 116 into a plurality of layers. Each layer may bein pneumatic communication via air passages 140 formed through walls138. Generally speaking, the more layers that rigidifying bladder 114has, the more rigid the bladder becomes under vacuum. Each of the layersmay include a pair of opposing layers of mesh 130 a and 130 b, as wellas a plurality of movable beads 132, as shown in FIGS. 12A and 12B. Theincreased rigidity results from the increased number of beads 132 whichmay be provided to lodge and engage with multiple sheets of mesh 130.The applied negative pressure increases the frictional forces betweenthe plurality of beads 132 and the mesh 130, as well as between eachother, which resists flexing and movement.

With particular reference to FIG. 16, rigidifying structure 120 mayinclude a plurality of dividing walls 142 extending between opposinglayers of mesh 130 a and 130 b, thereby dividing each layer of innerchamber 116 into a plurality of cells 144. Dividing walls 142 include atleast one air passage 146 for providing pneumatic communication betweenadjacent cells 144. Dividing walls 142 retain a predetermined number ofmovable beads 132 within each cell. Generally speaking, dividing walls142 prevent the migration of substantial numbers of the beads to one endof rigidifying bladder, thereby ensuring a consistent level of rigidityacross the extent of the bladder. To prevent the obstruction of airthrough port 118 and air passages 140 and 146, beads 132 may bemultifaceted or oversized to prevent an air-tight seal from being formedif a bead lodges in the port or one of the air passages. Alternatively,beads 132 may include holes formed therethrough to allow the passage ofair.

The dividing walls 142 are preferably collapsible to allow opposinglayers of mesh 130 a and 130 b to be drawn together (see FIG. 12B). Inthis regard, walls 142 may be made from a substantially resilientmaterial such as foam rubber which provides support when chamber 116 isat ambient pressure, as shown in FIG. 17A, and which compresses andcollapses when chamber is at negative pressure, as shown in FIG. 17B.Alternatively, dividing walls 142 may include a pivot point 148 as shownin FIG. 18 or a reduced-thickness area or crease 150 as shown in FIG. 19to facilitate the collapse or compression of walls 142.

As mentioned above, the tissue stabilizer of the present invention maybe configured to satisfy a wide range of applications. As alreadymentioned in reference to FIG. 15, tissue stabilizer 110 may beconfigured to stabilize an injured leg, for example, a broken leg.Referencing FIG. 20, exemplary tissue stabilizer 110 is configured toprovide support and stabilize the neck of an injured person. In thisembodiment, tissue stabilizer 110 may be carried by emergency rescueteams to remote locations for use in stabilizing potential victims ofneck and spinal injuries. At remote locations, a portable pump 152 maybe engaged with valve 136 and actuated to evacuate chamber 116 torigidify bladder 114. Portable pump 152 may be of the type analogous tothose used for inflating blood-pressure cuffs. Whereas conventional neckbraces are manufactured in standard sizes which might not fit allpatients, tissue stabilizer 110 of the present invention may becontoured to fit the neck of each individual patient, thereby providingmuch better support and stability.

Exemplary tissue stabilizer 110 may be configured to stabilize asprained wrist or broken arm, as illustrated in FIG. 21. In thisembodiment, tissue stabilizer 110 may include a plurality ofcomplementary pairs of straps 112 for attaching rigidifying bladder 114to the arm. In the case where a bone is broken (as shown in FIG. 15),tissue stabilizer 110 may serve as a cast, replacing conventionalplaster or fiberglass casts. A doctor may set the broken bone and thenapply the tissue stabilizer 110 in accordance with the foregoingdescription. The bone may be X-rayed to determine the integrity of theset. If the bone was set unsatisfactory, tissue stabilizer 110 may beremoved as described above, and the bone may be reset; thereafter, thetissue stabilizer may be reattached to the tissue and re-rigidified.

In addition to this temporary stabilization embodiment, tissuestabilizer 110 may be also configured to provide semi-permanent orpermanent stabilization for tissue. For example, an additional accessport (not shown) may be formed in rigidifying bladder 114 through whichadhesive, such as epoxy or glue, may be provided to fix the movablebeads 132 to mesh 130. The adhesive may be injected through theadditional access port or may be drawn into and dispersed throughoutchamber 116 under suction on port 118. Accordingly, once the adhesivesets, tissue stabilizer 110 will retain a desired shape and stabilizetissue even if chamber 116 loses a portion or all of the negativepressure by, for example, pneumatic leakage through valve 136.

As shown in FIG. 21, tissue stabilizer 110 may include a plurality ofvents 154 formed through bladder 114 to provide air circulation to theskin and relief to the patient. Vents 154 may be in the form of smallperforations formed through the bladder, and may be formed analogouslyto window 56 described above (see FIG. 1). In addition, tissuestabilizer 110 may be made from material such as silicone and nylonwhich may be exposed to water without adverse effects (as opposed toplaster casts), allowing a user to conveniently bath and allowing a userto clean the tissue stabilizer if soiled.

Another exemplary embodiment of the tissue stabilizer of the presentinvention is illustrated in FIG. 22, which is referenced by numeral 160.In this embodiment, tissue stabilizer 160 is configured to beincorporated into footwear, such as an athletic shoe 162. Many athleticshoes attempt to support a user's ankle to prevent injury. Athletic shoe162 of the present invention supports the ankle by including tissuestabilizer 160 which may be configured like a sock or a shoe liner tofit around a user's heel and/or ankle. Tissue stabilizer 160 includes avalve 164 through which rigidifying bladder (not shown) may be deflatedor evacuated and for sealing the bladder. In addition to athletic shoessuch as basketball shoes, the tissue stabilizer of the invention may beincorporated into skates (both in-line and ice), ski boots, hikingshoes, and so on. Alternatively, tissue stabilizer may be configured asan insole so that when rigidified, the stabilizer serves as an orthoticdevice.

In addition to the numerous applications described above, the teachingsof the present invention may be applied to other tissue supporting orstabilizing situations. In this regard, those skilled in the art willappreciated that the tissue stabilizer may be modified for use inaugmentation and cosmetic surgery, for example, in connection withpenile implants or breast implants, without departing from the teachingsof the present invention. Also, tissue stabilizers may be configured tosupport organs other than the heart described above. For example, tocontrol a hemorrhage in an organ such as the liver or the spleen, thetissue stabilizer may be wrapped about the organ to provide support. Insuch a hemorrhage control embodiment, the tissue stabilizer may includea collagen layer to facilitate homeostasis. Tissue stabilizer may alsobe configured for use in support and stabilizing prosthetics byproviding a connective interface between the prosthetic and the bone towhich it is connected. Furthermore, tissue stabilizer may beincorporated into protective clothing use in sport, for example, shinand chest guards, helmets, gloves, and so on. In these embodiments, thetissue stabilizer may include a layer of padding material to providecushion or shock absorbency between the tissue to be protected and therigid bladder.

As previously mentioned, the rigidifying bladder may be made fromsilicone impregnated with nylon (with the nylon comprising at least aportion of the rigidifying structure). The rigidifying bladder mayinclude natural fibers such as cotton (e.g., canvas) or metallic fiberssuch as stainless-steel mesh to provide durability. Alternatively,tissue stabilizer may be made from substantially resilient material,such as certain silicones, so as to stretch under sufficient force. Inaddition, rather than pneumatic evacuation of rigidifying bladder of theinvention, fluids other than air, such as hydraulics may be used. As analternative means for attaching the rigidifying bladder to tissue,rather than including straps 112, tissue stabilizer 110 may include alayer of adhesive coated onto one side of the rigidifying bladder 114with a peel-away backing. The layer of adhesive may be adhered directlyto the skin of the patient or to a layer of pre-wrap (as known in theart).

Those skilled in the art will understand that the preceding exemplaryembodiments of the present invention provide the foundation for numerousalternatives and modifications thereto. These other modifications arealso within the scope of the present invention. For example, in additionto stabilizing human tissue in medical applications, the tissuestabilizer of the present invention may be configured to stabilize otheranimal tissue in veterinarian applications and plant tissue in botanicalapplications. Other applications in which the stabilizer may providetemporary rigid support is in the building and construction industry. Inthis case, the stabilizer may be configured to be much larger than thatdescribed above and much more durable to withstand hazardous workingconditions. Accordingly, the present invention is not limited to theembodiments precisely shown and described above.

1. A method for facilitating a surgical procedure on a beating heart,said method comprising: placing a cardiac stabilizer on an epicardium ofthe beating heart; applying a vacuum to the stabilizer to contour thestabilizer to a surface topography of the epicardium of the beatingheart; applying a vacuum to rigidify the stabilizer; and delivering atherapy to the heart through the stabilizer while the heart remainssecurely retained by the stabilizer.
 2. A method as in claim 1, whereinthe cardiac stabilizer is positioned through a sternotomy.
 3. A methodas in claim 1, wherein the stabilizer is positioned through athoracotomy.
 4. A method as in claim 1, wherein the stabilizer ispositioned intercostally through a sheath.
 5. A method as in claim 1,wherein delivering a therapy comprises performing transmyocardialrevascularization with a delivery device positioned through a window inthe stabilizer.
 6. A method as in claim 1, wherein delivering a therapycomprises injection of an angiogenic or myocardial cell growth substancethrough a window in the stabilizer.
 7. A method for facilitating asurgical procedure utilizing a tissue stabilizer comprising: providing aconformable bladder including: a rigidifying component; a port throughwhich said bladder is evacuatable; a grid of windows defined over thebladder; and attaching means for securing said conformable bladder totissue; positioning said tissue stabilizer on tissue; attaching saidtissue stabilizer to the tissue with said attaching means; rigidifyingsaid tissue stabilizer by applying suction at said port; and deliveringa therapy to the heart through one or more of the windows.
 8. A methodfor stabilizing tissue as claimed in claim 7, further comprisingde-rigidifying said tissue stabilizer.
 9. A method for stabilizingtissue as claimed in claim 7, further comprising detaching said tissuestabilizer from the tissue.
 10. A method for stabilizing tissue asclaimed in claim 7, wherein said rigidifying and attaching steps arefacilitated by applying suction through a suction apparatus comprised ofthe conformable bladder, the suction apparatus configured to be attachedto tissue for stabilization, the suction apparatus facilitating creationof sub-atmospheric pressure between tissue and the suction apparatus,enabling attachment of said conformable bladder to tissue.
 11. A methodas in claim 7, wherein delivering a therapy comprises performingtransmyocardial revascularization with a delivery device positionedthrough a window in the stabilizer.
 12. A method as in claim 7, whereindelivering a therapy comprises injection of an angiogenic or myocardialcell growth substance through a window in the stabilizer.